The present invention relates to an apparatus and method for cutting an optical fiber so as to form a mirror cut end surface which is perpendicular to the longitudinal axis of the optical fiber, when the optical fiber is subject to connection, measurement, or the like.
FIG. 7 (PRIOR ART) shows a conventional optical fiber cutter. In the optical cutter, an upper casing 76 and a lower casing 71 are provided so as to be in opposition to each other and so as to be pivotal relative to each other through a pin 72. A flat spring 77 for mounting an optical fiber thereon is attached at one end to the lower casing 71. An optical fiber pressing member 75 attached at one end to the upper casing 76 is provided above the flat spring 77. A cutter arm 73 is rotatably attached at a base end to a center of the pin 72 and a free end of the cutter arm 73 extends under an end of the upper casing 76 and is provided with an injuring edge 74.
To operate the conventional apparatus, the coating of a coated optical fiber is removed at its end. The optical fiber is mounted on the flat spring 77 and the exposed optical fiber is pressed by the pressing member 75 so that it is held in position. If the free end of the upper casing 76 is pushed down, the injuring edge 74 moves down so as to initially injure the optical fiber mounted on the flat spring 77. The pressure exerted on the upper casing 76 is removed and then the flat spring 77 is bent to a position where it abuts a stop 78, so that the bending stress acts to cut the optical fiber at the position of the initial injury.
In such an optical fiber cutter, however, skill is required to cut an optical fiber so as to form a mirror cut end surface which is perpendicular to the longitudinal axis of the optical fiber, because the injuring edge makes an arcuate motion and the flat spring is supported in the form of a cantilever.
FIG. 8 (PRIOR ART) is a diagram of an alternative conventional cutter. A coated optical fiber 1 is grasped by a clamp 81 which is provided at its grasping surface with an elastic material 81a. An end portion of an exposed optical fiber 2 of the coated optical fiber 1 is grasped by another clamp 82 which is also provided at its grasping surface with an elastic material 82a, so that the optical fiber 2 is grasped substantially horizontally in the air between the clamps 81 and 82. In this state, an injuring edge 83 is urged against the optical fiber 2 so as to initially injure the optical fiber 2. Then, a pressing block 84 is pressed against the optical fiber 2 from the side opposite the initial injury so as to exert tension to the optical fiber 2, thereby cutting the optical fiber 2.
In such a cutter, however, there has been a problem in that the clamp 81 grasps the coated optical fiber 1 while the clamp 82 grasps the exposed optical fiber 2, and the grasping force varies in accordance with the clamping force of the clamps 81 and 82, so that the slip-grasping force of the clamps 81 and 82 is not constant. Thus, the depth of the initial injury and the tension exerted on the optical fiber 2 at the time of cutting vary, making it difficult to cut the optical fiber 2 so that a mirror cut end surface which is perpendicular to the longitudinal axis of the optical fiber 2 is formed.